The present invention relates to On-Board Oxygen Generating Systems (OBOGS) and, more particularly, to a system for providing temperature controlled supply air for OBOGS.
An On-Board Oxygen Generating System (OBOGS), typically used by military aircraft, allows an aircraft to generate its own oxygenated air during flight. The product air from the OBOGS may be channeled through a regulator for use as breathing air by pilots, and/or other persons onboard the aircraft, or may be stored in a tank for later use (i.e. emergency or back up oxygen requirements). The inlet air to be treated by the OBOGS typically comprises conditioned engine bleed air. The treatment or conditioning of the bleed air entering the OBOGS typically requires adjusting the temperature of the bleed air in order to bring it to an acceptable temperature for the OBOGS.
Conventional approaches for temperature control of the bleed air may include overcooling the bleed air, and subsequently heating the overcooled air through a heat exchanger, which may be warmed by hot air. Such active temperature control may typically be performed at a location remote from the OBOGS, for example, near an engine of the aircraft. As the OBOGS may typically be located near the aircraft cockpit, the air may travel through a long, uncontrolled heat path before reaching the OBOGS, and may subsequently lose or gain heat as it is conveyed to the OBOGS. In typical operations where air-flow may be particularly low (i.e. 2-3 pounds/min or 0.015-0.022 kg/s) such long path to the OBOGS may have an especially significant effect in failure to maintain the set temperature.
As can be seen, there is a need for an improved system for providing temperature controlled supply air for OBOGS that provides controlled, efficient, and cost effective temperature control of the supply air. A system is needed that reduces or eliminates the need for active control and reduces or eliminates temperature fluctuations due to uncontrollable environmental conditions.